They are using buses that are subject to traffic congestion.

The buses in the dedicated lanes are still much slower than rail.

And you are still working with internal combustion engines.

First, I am only speaking as Sun Metro's BRT Program Manager and my response is strictly relating to El Paso's Rapid Transit System (RTS):

-the system is not exclusively dedicate lanes, but mixed traffic for all of Mesa St. and only dedidcate on Oregon St. from UTEP to Downtown.

-the term "rapid" does not imply that the vehicles will travel in exclusive lanes, nor at a fast pace (the average speed for an articulated vehicle is approx 26MPH while rail is approx. 22mph), but the time savings making it "rapid" occur at the stations by reducing dwell time by incorporating pre-paid ticket vending to allow for fast boarding & alighting, on-board bike racks that are easily secured with ease, and a passive restraint arm system for wheelchairs that enable the disabled transit user to secure themselves and not have to utilize the driver to secure them (unless requested).

-While the vehicle is dynamic, use of Traffic Signal Priority (TSP, not emergency vehicle preemption), which are low priority communiations emitted by the vehicle to the traffic signal receiver that enables the green to be held additional seconds if the vehicle's signal is within the threshhold to be read or if at a stop condition, shortening by a few seconds the red phase of the mainline by shortening the green on the minor road.

-Sun Metro's fleet (articulated vehicles, buses, mini-buses, vans, and company cars) are not internal cumbustion, the transit buses and articulated vehicles Low Floor Compressed Natural Gas (CNG) and the tanks are store above the roof of the vehicle. The RTS vehicle is made by New Flyer and is the model Xcelsior.

I hope this may clear any misconceptions or misinformation.